1. Field of the Invention
This invention relates to a water repellent for automobile window glass. More particularly, this invention relates to a water repellent for glass which prevents rain drops from adhering to automobile window glass (e.g., windshield glass) even when the automobile is traveling in the rain at a low speed of less than about 50 km/hr and allows the automobile window glass to offer a perfect field of view.
2. Description of the Prior Art
A method for preventing window glass from retaining rain drops on the surface thereof and enabling it to secure a perfect field of view in the rain by subjecting the glass surface in advance to a treatment for imparting water repellency thereto has been proposed heretofore. The treating agent which is used for this treatment is called a water-repellent type treating agent and is composed of dimethyl polyorganosiloxane, an inorganic acid, and a water-type solvent (U.S. Pat. No. 3,579,540).
The conventional water-repellent type treating agent indeed enables automobile window glass to secure a perfect field of view while the automobile is traveling at a high speed because rain drops hitting the glass surface are blown away by the pressure of wind. However, since dimethyl polyorganosiloxane exhibits strong adhesion with water molecules, rain drops adhere to the glass surface to the extent of impairing the field of view of the glass while the automobile is traveling at a low speed.
An object of this invention is to provide a water repellent for automobile window glass which prevents rain drops from adhering to the surface of automobile window glass and enables the window glass to offer a perfect field of view in the rain even while the automobile is traveling even at a low speed.